CHSE VST on Physical Chemistry

 VST on Physical Chemistry : CHSE

F.M: 70          Time: 3 Hour

Answer all questions from Section - A, ten from Section - B and three from Section - C

Section - A    [1 X 10 = 10]

1.       Choose the correct answer

i.    The number of octahedral voids in a hexagonal unit cells is equal to

            a) 4                    b) 6                    c) 8                           d) 12

ii.           The F - centres in crystal defect related to

       a) electrons         b)  holes      c) metals            d) non metals

iii.      The amount of silver deposited by passing one faraday of current through

 silver nitrate solution is (atomic mass of Ag = 108)

a)      1.08g             b) 10.8g                c) 108g                 d) 2X108g

iv.    The charge required for the reduction of one mole MnO₄^- to MnO₂ is:

a)      1F                   b) 3F                      c) 5F                       d) 6F

v.      What flows in the internal circuit of a galvanic cell

a)      Ions               b) electrons        c) electricity        d) atoms

vi.     Which of the following is correct for a first order reaction,

a)      t_1/2 α a          b) t_1/2 α a^-1          c) t_1/2 α a⁰            d) t_1/2 α a²

vii.                Temperature dependent equation can be written as:

a)      ln k = ln A – Ea /RT                   c) ln k = ln A - e^{Ea /RT}

b)      ln k = ln A + e^{Ea /RT}                     d) ln k = ln A + e-^{Ea /RT}

viii. The rate of reaction for A + 2B --------> C is given by R = [A][B]². Order of

 the reaction is:

a)      3                      b)  6                       c) 5                         d) 7

ix.      Alum purifies muddy water by:

a)      Dialysis         b) Adsorption    c) Coagulation   d) Absorption

x.       Which of the following acts as a protective colloid?

a)      Gelatine                                       b) l c) oil-in-water emulsion        

b)      Silica gel                                       d)  all of these

2.        Choose the correct answer         [1 X 10 = 10]

i.     Which of the following expression gives the osmotic pressure of a solution

a)      Π = RT/C      b) Π = CRT          c) Π = VRT          d) Π =RC/T

ii.                   Which of the following pair form an ideal solution

a)      H₂O and HBr             c) C₆H₆ and CCl₄

b)     C₂H₅OH and CCl₄     d) All of these

iii.                  During electrolysis the reaction occurs at anode is:

a)      Reduction   b) oxidation        c) Redox              d) Hydrolysis

iv.    When an electric current is passed through acidulated water, 112 ml of H₂ is

 collected at NTP at cathode in 965 seconds. The current strength is:

a)      1 amp            b)0.5 amp            c) 0.1 amp           d) 2 amp

v.    Electrolytes conduct electricity due to movement of

a)      Atoms           b) ions c) electrons        d) molecules

vi.    A substance with half life 4 days is taken to another place in another 12

 days. The amount of substance left is:

a)      ¼                     b) 1/8                    c) 1/1/16              d)1/32

vii.  The half life period for a first order reaction is 10 minutes. The initial

 amount of the reaction is 0.8M and concentration at any instant is 0.01M. The

 time taken for the reaction is:

a)       10 min          b) 20 min             c) 30 min              d) 40 min

viii.        Zeta potential is due to

a)      Presence of cation c) presence of electrical double layer

b)      Presence of anion   d) all of these

ix.      The range of radius ratio 0.414 - 0.732 refers to which of the following:

          a) tetrahedral            b) Octahedral              c) BCC              d) trigonal

x.          the unit cell referring to a ≠ b ≠ c and alpha ≠ beta ≠ gama is 

a)   Adsorption      b) absorption       c) Coagulation       d) none

3.       Answer all questions                     [1 X 15 = 15]

i.        What is vacancy defect

ii.      Define emulsion with example.

iii. What are the two cases of metal excess defect?

iv.   Define occlusion

v.     What is the energy possessed by the activated complex?

vi.   Under what condition does the rate of reaction equal to the rate constant?

vii.  What is the molecularity and order of the reaction of acid hydrolysis of ethyl

 acetate?

viii.   Write the unit of molar conductance in SI unit?

ix.  What is the relation between standard emf of a cell with equilibrium

 constant ?

x.   What is the charge on one mole of carbonate ion?

xi.    Which will liberate hydrogen form dilute acid? Zn or Cu, why?

xii.  What is the change n free energy for a galvanic cell and electrolytic cell ?

xiii.  Define cryoscopic constant?

xiv. Two liquids A and B boil at 124⁰c and 180⁰c respectively. Which of them will

 have higher vapour pressure A 80⁰c?

xv.  Define isotonic solution

Section – B

4.        Answer any ten [2 X 10 = 20]

i.     Derive a relationship between radius of atom and corresponding radius

 octahedral void.

ii.   Why freezing point depression of 0.1 M NaCl solution is nearly twice that of

 0.1M glucose solution?

iii.  Write the difference between ideal and non ideal solution.

iv.  In a cell Zn/Zn²⁺//Cu²⁺/Cu, the standard electrode potential are E⁰Cu²⁺/Cu

 = 0.34 V and E⁰ Zn/Zn²⁺ = -0.76 V. Calculate the emf of a cell.

v.     Derive relationship between a, d, r in BCC unit cell. 

vi.   Define equivalent conductance. How is it related to specific conductance?

vii.    Define ECE

viii.   Write difference between order of reaction and molecularity of a reaction.

ix.  Define electroplating. Name the electrolyte for silver plating.

x.  A first order reaction is 25% complete in 30 minutes. Calculate the rate constant (specific reaction rate) and half life period.

xi.  Show activation energy and threshold energy graphically

xii.  Define pseudo first order reaction with example.

xiii. Write three differences between physical adsorption and chemical

 adsorption.

xiv.   Define Tyndal effect.

Section – C [5 X 3 = 15]

5.        State and explain Galvanic cell.

6.    Write the postulates of collision theory of reaction rate and what are the limitations?

7.        Define boiling point. Show that elevation in boiling point is a colligative property.

8.       Write the difference between true solution, Colloidal solution and suspension.

9.      State and explain faraday’s second law of electrolysis. 3 faraday of electricity is passed through molten Al₂O₃ , aqueous solution of CuSO₄ and molten NaCl taken in different electrolytic cells. Calculate the molar ratio of Al, Cu and Na deposited at cathode.

 

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